DIRECTORY(V) 9/10/73 DIRECTORY(V)
NAME
dir - format of directories
DESCRIPTION
A directory behaves exactly like an ordinary file, save that
no user may write into a directory. The fact that a file is
a directory is indicated by a bit in the flag word of its i-
node entry. Directory entries are 16 bytes long. The first
word is the i-number of the file represented by the entry,
if non-zero; if zero, the entry is empty.
Bytes 2-15 represent the (14-character) file name, null
padded on the right. These bytes are not cleared for empty
slots.
By convention, the first two entries in each directory are
for ``.'' and ``..''. The first is an entry for the direc-
tory itself. The second is for the parent directory. The
meaning of ``..'' is modified for the root directory of the
master file system and for the root directories of removable
file systems. In the first case, there is no parent, and in
the second, the system does not permit off-device refer-
ences. Therefore in both cases ``..'' has the same meaning
as ``.''.
SEE ALSO
file system(V)
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